Influence of hole mobility on the response characteristics of p-type nickel oxide thin film based glucose biosensor

Abstract

RF sputtered p-type nickel oxide (NiO) thin film exhibiting tunable semiconductor character which in turns enhanced its functional properties. NiO thin film with high hole mobility is developed as a potential matrix for the realization of glucose biosensor. NiO thin film prepared under the optimized deposition conditions offer good electrical conductivity (1.5×10(-3) Ω(-1)-cm(-1)) with high hole mobility (2.8 cm(2) V(-1) s(-1)). The bioelectrode (GO(x)/NiO/ITO/glass) exhibits a low value of Michaelis-Menten constant (K(m)=1.05 mM), indicating high affinity of the immobilized GO(x) toward the analyte (glucose). Due to the high surface coverage (2.32×10(-7) mol cm(-2)) of the immobilized enzyme on to the NiO matrix and its high electrocatalytic activity, the prepared biosensor exhibits a high sensitivity of 0.1 mA(mM(-1)-cm(-2)) and a good linearity from 25 to 300 mg dL(-1) of glucose concentration with fast response time of 5 s. Various functional properties of the material (mobility, crystallinity and stress) are found to influence the charge communication feature of NiO thin film matrix to a great extent, resulting in enhanced sensing response characteristics.